Lowering machine



' Aug. 25,1931.-

3 Sheets-Sheet 1 I ATTORNEYS Aug. 25, 19 1. 0., BIRMANN I LOWERING MACHINE Filed Jan. 14. 1929 3 Sheets-Sheet 2 INVENTOR tr'manm 25, 1931. 'o. BIRMANV'N LOWERING MACHINE 3 Sheets-Sheet 3 Find Jan. 14. 1929 I INVENT/OR %M a ATTORNEYS I we Patented Aug. 25,1931

1::5 o'r'romnmnnnor enson, NEW

YORK, 1 AssIGNon 'ro' elrronnewoon O PANY, or

"HUDSON, NEW YORK, A CORPORATION-F;NEW- YQRK= g LowERr vo MAoHINE' Application filed iaiiuary 14, 1929. Serial No. 332,459. g,

This invention relates to improvements in elevators and, among other ObJGClZS, aims to provide an improved elevator installation" andmeans to prevent the elevator from fallin should the supporting cable break.

' n the drawings,

' Fig. 1 is aside elevation ofone embodiment of the invention;

, "Fig. 2 is a side elevation {'onan enlarge'd p scale of a portion ofthe elevator sho ing Fig. 5 is a vertical-sectional view taken at right angles to Fig. 4; and

A Fig. 6 is a horizontal sectional view'take'n on the line 6'-6 of Fig.3.

Referring particularly to thedraw'ings, the improved mechanism is shown as being applied to' anelevator of the type generally used in ice plants, which'consists essentially of a counterweightedplatformor gig -10 sup-- ported at both ends and mounted to slide vertically on timber-covered standards or guides 11. These elevators are normally used for lowering ice or the'like from one level S6 to a lower level,the'counterweights being so adjusted that they" are heavier than the empty gig, thus. causing the gig to ascend,

and lighter than the loaded gig, which will descend of its own weight. I

The gig isusually held in'both the top'and bottom positions by manually operated catches (not shown) which, ofcourse, must be released or the'empty gig ascends, as the case may be.

To prevent a too rapid descent or-ascent,the

counterweights move up and down incylinders which are filled with a liquid, thus checking travel of the counterweights, but

7 g a as this feature'forms no part of the present 4 invention, it has not been shown.

In such elevator installationa'the gig-is usually supported by a rope or cable at each end and one or both ofthe cables, in time,

are liable to break, so that the gig drops with its load. Exceptonvery rare occasions, only scale taken through the cable strips of wood 21 secured: to

, .supportthe gig. beforethe loaded gig descends one rope breaks,-th I in a canted position and spill its load or fall to the lower level,"so that the gig is damaged by being sprung out ofshape,

The present invention 'obvi-ates these unand hold thegig on an even keel at any oint of'i'ts travelg should the supporting cable break. "To this end, only-one rope or cable12 is empl0yed,thesame being secured scausing the gig to fall I A desirable results by a novel cable arrange I men't combined with means which will catch H T at its ends to oounterweights 13 {at opposite ends of the elevator and passing over guide sheavesll at the top of the supportinglstruoe ture underslidably mounted sheaves 15 at each end of the gig, the sheaves'l5 being operatively connected to safety devices; (about'to be described) in such a; mannerthat the safety devices are=held in inoperative or 'normal position so long-as the cable re mains-inta'ct-and taut,

-Each' of the safety-devicegof which there is one at each end of'the gig, comprises a pair of gripping dogs 16 (Fig. 3), eccent-ricallymounted for oscillation on horizontal shafts to the end -Wall'19 of the gig and'to' the upper framework 20} *The dogs-0f each pair are arranged oppos'ite 1 to each other and on op posite SldGSOfiLIld in vertical alignment with guidefll (Figs. 2,3 6). The dogs are each formed with"transverse teeth on the curved 'side'adj acent to-the strip 21 and are soarranged thatwhen-they are rocked, their teeth willflbite into .thefwooden strips and The mechanism for actuating eaeh'set of dogs is'shown in Figs. '2 and 3 ascomprising a'vertically disposedplunger 22 slidably mounted in agui'de member .23securedbnthe outside of the endwall719. The upper end ofthe plunger 22, which extends above the adjacent lid theguide member 23," is bifurcated as shown inJFigs; 3 and 6', so that one ofthe'sheaves 15 may-be rotatably mounted between theside arms on asuitableshaftor axle'.'a:The'

plungerextendsbelow' the guide memberi23' andcarries a crosshead 24 at its lower end.

This endof the'pluhger is preferably screw- 76 I 17 carriedby supporting bracl'rets 183secured justed vertically on the plunger. A crank 26 (Fig. 3) is secured to or-formed integrally with each dog and extends outwardly therefrom and is pivotally Connected to the upper end of a link 27, whose lower end is pivotally connected to one side of the erosshead. An expansile coil spring 28 is shown surrounding the plunger between the crosshead and the lower end of the guide member, normally urging the dogs toward their gripping positions.

To support the gigby the cable 12, the guide members 23 are preferably shaped like an inverted U, to provide a supporting bail 29, and the sheave 15 (which normally does not rotate), is adapted to abut against the lower side of the bail, so that the gig is sup: ported directly on the two sheaves 15 which in turn are supported by the cable passing beneath them, as before described. The sheave pin extends through vertical slots in the sides of the bail. This arrangement relieves the plunger and all of the moving parts of all strain. a

The weight of the gig (whether loaded or empty) keeps the cable taut and holds both plungers 22 in their uppermost or normal position, as shown in Fig. 3, with the dogs out of engagement with the wooden strips and with the springs 28 compressed. Should the tension on the cable be released, as by breaking, the springs 28 would expand and force the crossheads downwardly, thereby rocking the dogs inwardly against the strips by means of the link connections, so that the teeth bite into the strips and thus prevent the gig from falling. By using but a single cable, it is apparent that should it break at any point, the tension would be released through out the entire length and both of the gripping devices would operate instantly and simultaneously to support both ends of the gig on an even keel.

As but one rope is used, it is evident that should the gig be loaded unevenly, or should the friction on the guides be unequal, a certain amount of slip and creeping of the cable would occur, permitting the gig to cant so that one end would be higher than the other or one counterweight higher than the other, causing one weight to strike the bottom or top of the cylinder in which it is mounted before the gig had completed its travel.

To prevent the canting, a device is provided to grip the cable at its approximate mid length, so that the cable in effect becomes two cables, each secured at one end to a coun terweight and at the other end to one end of the gig. The device is constructed so that should the cable break, the grip would be released.

The gripping device is herein shown as comprising a cluster of three sheaves 30, 31 and 32 (Figs. 1, 4t and 5) arranged on the top of the upper framework 20. The two sheaves 30 and 32 are mounted in both horizontal and vertical alignment in a stationary bracket 33, the distance between their adjacent edges being less than thediameter of the third sheave 31, which is located above and in vertical alignment with them on a vertically slidable support 34:. The cable passes beneath the two side sheaves 30 and 32 and over the central sheave 31, so that the tension in the cable draws the sheave 31 down, compressing an expansile coil spring 35 which surrounds the support between the framework and an abutment 36 on the support.

The grooves in all of the sheaves are of less depth than half the diameter of the cable so that the cable is normally gripped between the sheaves 30 and 32 and the sheave 81, when the latter is drawn downwardly. In case the cable breaks at any point, its tension will be lost and the spring 35 will force the central sheave 31 upwardly thereby releasing the grip on the cable and permitting both sets of dogs to operate.

From the foregoing description it will be apparentthat the improved gripping devices and cable sheaves may easily be applied to an old elevator so that it can be operated by a single cable. Moreover, the attachment can be manufactured at a very low cost. Further, the mechanism is arranged positively to prevent the elevator from falling or canting as soon as the single cable becomes slack from whatever cause.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shownand described. Moreover, it is not indispensable that all the features of the invention be used conjointly, since they may be employed advantageously in various combinations and sub-combinations.

What I claim is 1 1. An elevator installation comprising, in combination, a pair of vertical guides; an elevator slidably mounted on said guides; a sheave at the top of each guide; a slidably mounted sheave at each end of the elevator; a cable having lifting weights secured to its ends, said cable passing over the two sheaves at the top of the guides and beneath the slida-. ble sheaveswith its mid portion between said slidable sheaves; means connected to the slidable sheaves to engage the guides and prevent the elevator from falling when the cable breaks; and means on the elevator to grip the cable intermediateits ends when the cable is taut and to release the grip when the cable breaks.

2. An elevator installation comprising, in combination, apair of vertical guides, an ele vator slidably mounted on said guides; at

l sheave at the top of each guide; a slidably mounted sheave at each end of the elevator;

a cable having lifting weights secured to its ends, said cable passing over the two sheaves at the top vof the guidesand beneath the slidable sheaves with its mid portion between said slidable sheaves;a pair of dogs at each end of the elevator arranged to engage the guides when released; and means operably connected to each pair of dogs and to the adjacent slidable sheave to release said dogs when the cable breaks.

3. An elevator installation com rising, in combination, a pair of vertical gui es; an elevator slidab'ly mounted on the guides; a

' sheave at each end of the elevator; a lifting V to end and beneath both sheaves; means op- V cable for the elevator; said cable extending across the elevator from end to end and beneath both sheaves; and means intermediate the sheaves at the ends'of the elevator for clamping the cable, said means automatically releasing the cable when the cable breaks.

4. An elevator installation comprising, in

combination, a pair of vertical guides; an elevator slidably mounted on the guides; a slid ably mounted sheave at eachendof the elevator; a lifting cable for the elevator; said cable extending across the elevator from end erably connected to each sheave to engage the guides and prevent the elevator from falling when the cable breaks; and means onthe elevator to gripthe cable between the sheaves and prevent its movement relative to the,

sheaves-when the cable is taut and to release the grip when the cable breaks. v

5. An elevator installation comprising, in combination, a pair of vertical'guides; an elevator slidably mounted'on the guides; a slidably mounted sheave at eachend of the ele- 1 vator; a lifting cable for the elevator; said cable extending acrossthe elevator from end to end and beneath both sheaves; a pair ,of

plungers being adapted to actuate the gripping dogs simultaneously at both ends of the platform when the cable breaks, 7; An elevator installation comprising, in

combination, a pair of vertical guides, an ele- 'vator slidably mounted on said'guides; a slidablyinounted sheave at eachend of the elevator; an elevator-supporting cable passing beneath the slidable sheaves; a pair of arcuate dogs eccentrically pivoted to the elevator at each end thereof and on each side of the guides, said dogs having transverse teeth for engagement with said guides; and mechanism connecting the slidable sheaves with said dogs so that the dogs automatically engage the guides and prevent the elevator from fall- OTTO 'BIRMANN.

gripping dogs rockably mounted at each end 7 v of the elevator, the dogs in each pair being on opposite sides of a guide to-engage said guide when released; and means operably connect- 1 ed to each of the sheaves and to theadjacent pair of dogs to release the dogs when the cable breaks and permit the dogs to engage theguidesh 6. In an elevator of the class described, a substantially rectangular load platform; ver-' tical guides at the opposite ends .of the pl atform; cable sheaves supported on the guides at the upper ends; a cable sheave at each end of the platform adjacent to vertical guides;

a vertical plunger supporting each sheave;

a pair of pivoted gripping dogs on opposite sides of each guide; links connecting the 7 lower ends of the plungers with the dogs; a spring associated with each plunger arranged to operate the gripping dogs; and'a single lifting cable trained over the sheaves on the guides'and underthe sheaves on theplatform normally to hold the gripping dogs.

inactive when the cable is taut, said spring iao 

